Reactors having gas distributors and methods for depositing materials onto micro-device workpieces

ABSTRACT

Reactors having gas distributors for depositing materials onto micro-device workpieces, systems that include such reactors, and methods for depositing materials onto micro-device workpieces are disclosed herein. In one embodiment, a reactor for depositing material on a micro-device workpiece includes a reaction chamber and a gas distributor in the reaction chamber. The gas distributor includes a first gas conduit having a first injector and a second gas conduit having a second injector. The first injector projects a first gas flow along a first vector and the second injector projects a second gas flow along a second vector that intersects the first vector in an external mixing zone facing the workpiece. In another embodiment, the mixing zone is an external mixing recess on a surface of the gas distributor that faces the workpiece.

TECHNICAL FIELD

The present invention is related to reactors having gas distributors and methods for depositing materials in thin film deposition processes used in the manufacturing of micro-devices.

BACKGROUND

Thin film deposition techniques are widely used in the manufacturing of micro-devices to form a coating on a workpiece that closely conforms to the surface topography. The size of the individual components in the devices is constantly decreasing, and the number of layers in the devices is increasing. As a result, the density of components and the aspect ratios of depressions (e.g., the ratio of the depth to the size of the opening) are increasing. The size of workpieces is also increasing to provide more real estate for forming more dies (i.e., chips) on a single workpiece. Many fabricators, for example, are transitioning from 200 mm to 300 mm workpieces, and even larger workpieces will likely be used in the future. Thin film deposition techniques accordingly strive to produce highly uniform conformal layers that cover the sidewalls, bottoms, and corners in deep depressions that have very small openings.

One widely used thin film deposition technique is Chemical Vapor Deposition (CVD). In a CVD system, one or more precursors that are capable of reacting to form a solid thin film are mixed in a gas or vapor state, and then the precursor mixture is presented to the surface of the workpiece. The surface of the workpiece catalyzes the reaction between the precursors to form a thin solid film at the workpiece surface. The most common way to catalyze the reaction at the surface of the workpiece is to heat the workpiece to a temperature that causes the reaction.

Although CVD techniques are useful in many applications, they also have several drawbacks. For example, if the precursors are not highly reactive, then a high workpiece temperature is needed to achieve a reasonable deposition rate. Such high temperatures are not typically desirable because heating the workpiece can be detrimental to the structures and other materials that are already formed on the workpiece. Implanted or doped materials, for example, can migrate in the silicon substrate at higher temperatures. On the other hand, if more reactive precursors are used so that the workpiece temperature can be lower, then reactions may occur prematurely in the gas phase before reaching the substrate. This is not desirable because the film quality and uniformity may suffer, and also because it limits the types of precursors that can be used.

One conventional system to prevent premature reactions injects the precursors into the reaction chamber through separate ports. For example, each port of a shower head can be coupled to a dedicated gas line for a single gas. Systems that present the precursors through dedicated ports proximate to the surface of the workpiece, however, may not sufficiently mix the precursors. Accordingly, the precursors may not react properly to form a thin solid film at the workpiece surface. Furthermore, conventional systems also have a jetting effect that produces a higher deposition rate directly below the ports. Thus, conventional CVD systems may not be appropriate for many thin film applications.

Atomic Layer Deposition (ALD) is another thin film deposition technique. FIGS. 1A and 1B schematically illustrate the basic operation of ALD processes. Referring to FIG. 1A, a layer of gas molecules A_(x) coats the surface of a workpiece W. The layer of A_(x) molecules is formed by exposing the workpiece W to a precursor gas containing A_(x) molecules, and then purging the chamber with a purge gas to remove excess A_(x) molecules. This process can form a monolayer of A_(x) molecules on the surface of the workpiece W because the A_(x) molecules at the surface are held in place during the purge cycle by physical adsorption forces at moderate temperatures or chemisorption forces at higher temperatures. The layer of A_(x) molecules is then exposed to another precursor gas containing B_(y) molecules. The A_(x) molecules react with the B_(y) molecules to form an extremely thin layer of solid material on the workpiece W. The chamber is then purged again with a purge gas to remove excess B_(y) molecules.

FIG. 2 illustrates the stages of one cycle for forming a thin solid layer using ALD techniques. A typical cycle includes (a) exposing the workpiece to the first precursor A_(x), (b) purging excess A_(x) molecules, (c) exposing the workpiece to the second precursor B_(y), and then (d) purging excess B_(y) molecules. In actual processing several cycles are repeated to build a thin film on a workpiece having the desired thickness. For example, each cycle may form a layer having a thickness of approximately 0.5-1.0 Å, and thus it takes approximately 60-120 cycles to form a solid layer having a thickness of approximately 60 Å.

FIG. 3 schematically illustrates an ALD reactor 10 having a chamber 20 coupled to a gas supply 30 and a vacuum 40. The reactor 10 also includes a heater 50 that supports the workpiece W and a gas dispenser 60 in the chamber 20. The gas dispenser 60 includes a plenum 62 operatively coupled to the gas supply 30 and a distributor plate 70 having a plurality of holes 72. In operation, the heater 50 heats the workpiece W to a desired temperature, and the gas supply 30 selectively injects the first precursor A_(x), the purge gas, and the second precursor B_(y) as shown above in FIG. 2. The vacuum 40 maintains a negative pressure in the chamber to draw the gases from the gas dispenser 60 across the workpiece W and then through an outlet of the chamber 20.

One drawback of ALD processing is that it has a relatively low throughput compared to CVD techniques. For example, ALD processing typically takes several seconds to perform each A_(x)-purge-B_(y)-purge cycle. This results in a total process time of several minutes to form a single thin layer of only 60-100 Å. In contrast to ALD processing, CVD techniques require much less time to form similar layers. The low throughput of existing ALD techniques limits the utility of the technology in its current state because ALD may be a bottleneck in the overall manufacturing process. Thus, it would be useful to increase the throughput of ALD techniques so that they can be used in a wider range of applications. Another drawback of ALD processing is that it is difficult to control the uniformity of the deposited films because the holes 72 in the distributor plate 70 also cause a jetting affect that results in a higher deposition rate in-line with the holes 72. Therefore, a need exists in semiconductor fabrication to increase the deposition uniformity in both CVD and ALD processes.

SUMMARY

The present invention is directed toward reactors having gas distributors for depositing materials onto micro-device workpieces, systems that include such reactors, and methods for depositing materials onto micro-device workpieces. In one embodiment, a reactor for depositing material onto a micro-device workpiece includes a reaction chamber and a gas distributor in the reaction chamber. The gas distributor includes a first gas conduit having a first injector and a second gas conduit having a second injector. In one aspect of this embodiment, the first injector projects a first gas flow along a first vector and the second injector projects a second gas flow along a second vector that intersects the first vector in a mixing zone. In another aspect of this embodiment, the gas distributor can also include a mixing recess that defines the mixing zone. The mixing recess can have a variety of configurations, such as a conical, cubical, cylindrical, frusto-conical, pyramidical or other configurations. The first injector can project the first gas flow into the mixing recess along the first vector, and the second injector can project the second gas flow into the mixing recess along the second vector. In a further aspect of this embodiment, the first and second injectors are positioned within the mixing recess. The mixing zone can be positioned partially within the mixing recess.

In another embodiment, a reactor for depositing material onto a micro-device workpiece includes a reaction chamber, a workpiece support in the reaction chamber, and a gas distributor with a mixing recess in the reaction chamber. The mixing recess is exposed to the workpiece support. The gas distributor includes a first gas conduit having a first injector and a second gas conduit having a second injector. The first injector projects a first gas flow into the mixing recess along a first vector and the second injector projects a second gas flow into the mixing recess along a second vector.

These reactors can be used to perform several methods for depositing materials onto micro-device workpieces. In one embodiment, a method includes flowing the first gas through the first injector of the gas distributor along a first vector, and flowing the second gas through the second injector of the gas distributor along a second vector. The second vector intersects the first vector in the mixing zone over the micro-device workpiece. In another embodiment, a method includes flowing the first gas through the first injector of the gas distributor into the mixing recess, and flowing the second gas through the second injector of the gas distributor into the mixing recess over the micro-device workpiece. In a further embodiment, a method includes dispensing a first pulse of the first gas from a first outlet into a recess in the gas distributor, and dispensing a second pulse of the second gas from a second outlet into the recess in the gas distributor after terminating the first pulse of the first gas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic cross-sectional views of stages in ALD processing in accordance with the prior art.

FIG. 2 is a graph illustrating a cycle for forming a layer using ALD in accordance with the prior art.

FIG. 3 is a schematic representation of a system including a reactor for depositing a material onto a microelectronic workpiece in accordance with the prior art.

FIG. 4 is a schematic representation of a system having a reactor for depositing material onto a micro-device workpiece in accordance with one embodiment of the invention.

FIG. 5 is a schematic representation of the gas distributor shown in FIG. 4 having a plurality of mixing recesses.

FIG. 6 is a bottom view of one mixing recess taken substantially along the line A-A of FIG. 5.

FIGS. 7A-7D are schematic representations of portions of gas distributors having mixing recesses in accordance with additional embodiments of the invention.

FIG. 8 is a schematic representation of a gas distributor in accordance with another embodiment of the invention.

FIG. 9 is a schematic representation of a gas distributor in accordance with another embodiment of the invention.

DETAILED DESCRIPTION

The following disclosure describes several embodiments of reactors having gas distributors for depositing material onto micro-device workpieces, systems including such reactors, and methods for depositing materials onto micro-device workpieces. Many specific details of the invention are described below with reference to depositing materials onto micro-device workpieces. The term “micro-device workpiece” is used throughout to include substrates upon which and/or in which microelectronic devices, micromechanical devices, data storage elements, read/write components, and other features are fabricated. For example, micro-device workpieces can be semiconductor wafers, such as silicon or gallium arsenide wafers, glass substrates, insulative substrates, and many other types of materials. The term “gas” is used throughout to include any form of matter that has no fixed shape and will conform in volume to the space available, which specifically includes vapors (i.e., a gas having a temperature less than the critical temperature so that it may be liquefied or solidified by compression at a constant temperature). Several embodiments in accordance with the invention are set forth in FIGS. 4-9 and the following text to provide a thorough understanding of particular embodiments of the invention. A person skilled in the art will understand, however, that the invention may have additional embodiments, or that the invention may be practiced without several of the details of the embodiments shown in FIGS. 4-9.

A. Deposition Systems

FIG. 4 is a schematic representation of a system 100 for depositing material onto a micro-device workpiece in accordance with one embodiment of the invention. In this embodiment, the system 100 includes a reactor 110 having a reaction chamber 120 coupled to a gas supply 130 and a vacuum 140. For example, the reaction chamber 120 can have an inlet 122 coupled to the gas supply 130 and an outlet 124 coupled to the vacuum 140.

The gas supply 130 includes a plurality of gas sources 132 (identified individually as 132 a-c), a valve assembly 133 having a plurality of valves, and a plurality of gas lines 136 and 137. The gas sources 132 can include a first gas source 132 a for providing a first precursor A, a second gas source 132 b for providing a second precursor B, and a third gas source 132 c for providing a purge gas P. The first and second precursors A and B are the gas or vapor phase constituents that react to form the thin, solid layer on the workpiece W. The purge gas P can be a suitable type of gas that is compatible with the reaction chamber 120 and the workpiece W. The gas supply 130 can include more gas sources 132 for applications that require additional precursors or purge gases in other embodiments. The valve assembly 133 is operated by a controller 142 that generates signals for pulsing the individual gases through the reaction chamber 120.

The reactor 110 in the embodiment illustrated in FIG. 4 also includes a workpiece support 150 and a gas distributor 160, such as a shower head, in the reaction chamber 120. The workpiece support 150 is typically heated to bring the workpiece W to a desired temperature for catalyzing the reaction between the first precursor A and the second precursor B at the surface of the workpiece W. The workpiece support 150 is a plate with a heating element in one embodiment of the reaction chamber 120. The workpiece support 150, however, may not be heated in other applications.

B. Gas Distributors

FIG. 5 is a schematic representation of the gas distributor 160 shown in FIG. 4 having a plurality of mixing recesses 280. In this embodiment, the gas distributor 160 has a first surface 262 with mixing recesses 280 that provide zones in which gas flows can mix before flowing to the workpiece W. In CVD applications, the precursors A and B can mix in the recesses 280 before flowing to the workpiece W. In ALD applications, precursor A can mix in the recesses 280 during a pulse and then precursor B can mix in the recesses 280 during a subsequent pulse after alternating purge gas P pulses. The mixing recesses 280 can be spaced uniformly throughout the first surface 262 to provide constant volumes over the entire workpiece W. In this embodiment, the mixing recesses 280 have a generally frusto-conical shape with a first wall 282 defining the side of the conical section and a second wall 284 defining the bottom of the mixing recess 280. In other embodiments explained below, the mixing recesses 280 can have other shapes, such as those described below with reference to FIGS. 7A-7D; in additional embodiments explained below, the gas distributor 160 may not have mixing recesses 280, such as the embodiment described below with reference to FIG. 9.

In the embodiment illustrated in FIG. 5, the gas distributor 160 includes a plurality of first injectors 270 positioned in the first wall 282, a plurality of second injectors 272 positioned in the first wall 282 at different locations, and a plurality of third injectors 274 positioned in the second wall 284. The injectors 270, 272, and 274 are oriented to project gas flows into the mixing recesses 280. The first injectors 270 are coupled to the first gas source 132 a by a first gas conduit 232 a. The first gas conduit 232 a receives the first precursor A from the gas line 137 at the inlet 122 and distributes the first precursor A throughout the gas distributor 160 to the first injectors 270. Similarly, the second injectors 272 are coupled to the second gas source 132 b by a second gas conduit 232 b, and the third injectors 274 are coupled to the third gas source 132 c by a third gas conduit 232 c.

Each of the first injectors 270 is oriented to project a first gas flow into the mixing recesses 280 along a first vector V₁ at an angle σ with respect to the workpiece W. Each of the second injectors 272 is oriented to project a second gas flow into the mixing recesses 280 along a second vector V₂ at an angle α with respect to the workpiece W. The second vector V₂ forms an angle β with respect to the first vector V₁. In the illustrated embodiment, the second vector V₂ is transverse (i.e., non-parallel) to the first vector V₁. In other embodiments, such as the embodiment described below with reference to FIG. 7A, the second vector V₂ can be generally parallel to the first vector V₁. The first vector V₁ intersects the second vector V₂ at an intersection point 292 in a mixing zone 290 located proximate to the workpiece W. Each of the third injectors 274 is oriented to project a third gas flow into the mixing recesses 280 along a third vector V₃ at an angle θ with respect to the workpiece W.

FIG. 6 is a bottom view of one mixing recess 280 of the gas distributor 160 taken substantially along the line A-A of FIG. 5. In the illustrated embodiment, the mixing recess 280 includes a plurality of first injectors 270 (identified individually as 270 a-c) and a plurality of second injectors 272 (identified individually as 272 a-c) in the first wall 282 positioned annularly around the third injector 274. In other embodiments, the first injectors 270, the second injectors 272, and/or the third injector 274 can be arranged in different patterns or configurations. For example, the mixing recess 280 can have only one first injector 270, one second injector 272, and one third injector 274, or the mixing recess can have a plurality of third injectors 274 located in the first wall 282 interspersed between the first injectors 270 and the second injectors 272. In further embodiments, some of the first injectors 270 and/or second injectors 272 can be positioned in the second wall 284.

C. Methods for Depositing Material on Micro-Device Workpieces

Referring to FIG. 5, in one aspect of the embodiment, the gas distributor 160 can be used in CVD processing. For example, the first injectors 270 can project the first precursor A along the first vector V₁ into the mixing zones 290, and the second injectors 272 can simultaneously project the second precursor B along the second vector V₂ into the mixing zones 290. Accordingly, the first and second precursors A and B mix together in the mixing zones 290. The orientation of the first and second injectors 270 and 272 (and accordingly the first and second vectors V₁ and V₂) facilitates the mixing of the first and second precursors A and B by flowing the gases into each other. Consequently, a mixture of the first and second precursors A and B is presented to the workpiece W.

In a further aspect of this embodiment, the gas distributor 160 can be used in both continuous flow and pulsed CVD applications. In a pulsed CVD application, a pulse of both the first precursor A and the second precursor B can be dispensed substantially simultaneously. After a pulse of the first and second precursors A and B, the third injector 274 can dispense a pulse of purge gas P along the third vector V₃ into the mixing recesses 280 to purge excess molecules of the first and second precursors A and B. After purging, the process can be repeated with pulses of the first and second precursors A and B. In another pulsed CVD application, the purge gas P flows continuously and pulses of the first and second precursors are injected into the continuous flow of the purge gas. The purge gas P, for example, can flow continuously along the third vector V₃.

In another aspect of this embodiment, the gas distributor 160 can be used in ALD processing. For example, the first injectors 270 can project the first precursor A containing molecules A_(x) into the mixing recesses 280. In the illustrative embodiment, the orientation of the first injectors 270 in the mixing recesses 280 causes the first precursor molecules A_(x) to mix sufficiently to form a uniform layer across the surface of the workpiece W. Next, the third injector 274 can project the purge gas P to purge excess first precursor molecules A_(x) from the mixing recesses 280. This process can form a monolayer of A_(x) molecules on the surface of the workpiece W because the A_(x) molecules at the surface are held in .place during the purge cycle by physical adsorption forces at moderate temperatures or chemisorption forces at higher temperatures. The second injectors 272 can then project the second precursor B containing B_(y) molecules into the mixing recesses 280. The B_(y) molecules also mix and form a uniform layer across the surface of the workpiece W. The A_(x) molecules react with the B_(y) molecules to form an extremely thin solid layer of material on the workpiece W. The mixing recesses 280 are then purged again and the process is repeated.

In a further aspect of this embodiment, the first and second injectors 270 and 272 can sequentially project the first and second precursors A and B to induce a vortex within the mixing recesses 280 in order to further increase the mixing. For example, referring to FIG. 6, the first injector 270 a may dispense a first pulse of gas, followed by pulses from the first injector 270 b and then the first injector 270 c. In another aspect of this embodiment, the first injector 270 a and the second injector 272 a can dispense pulses of gas simultaneously, after which the first and second injectors 270 b and 272 b can dispense pulses simultaneously, and then the first and second injectors 270 c and 272 c can dispense pulses simultaneously. Accordingly, the first and second injectors 270 and 272 can sequentially project the first and second precursors A and B to increase mixing within the mixing recesses 280.

One advantage of this embodiment with respect to the CVD process is that by using dedicated injectors 270, 272 and 274 and gas conduits 232 for each gas, the precursors A and B are kept separate, and accordingly, do not react prematurely. Furthermore, because the precursors A and B do not react prematurely, precursors that are highly reactive can be used, avoiding the need to heat the workpiece W to detrimentally high temperatures. Another advantage of this embodiment with respect to the ALD and CVD processes is that the enhanced mixing of the gases reduces the jetting effect and creates a uniform deposition across the surface of the workpiece W. A further advantage of this embodiment is that the position of the purge gas injectors 274 at the base of the mixing recesses 280 prevents the other gases from being trapped in the mixing recesses 280. Another advantage of this embodiment is that the flow to each mixing recess can be independently controlled to compensate for nonuniformities on the workpiece W. For example, if the surface at the center of the workpiece W is too thick, the flow of gases from the injectors over the center of the workpiece W can be reduced. Still another advantage is that the chemical composition of the deposited film can be controlled precisely because the mixing at the outlets provides more precise reactions at the workpiece surface.

D. Other Gas Distributors

FIGS. 7A-7D are scherriatic representations of portions of gas distributors having mixing recesses and injectors in accordance with additional embodiments of the invention. Each figure illustrates a different mixing recess and a particular arrangement of injectors; however, each arrangement of injectors can be used in conjunction with any of the mixing recesses. For example, the injector arrangements with only first and second injectors, such as those disclosed with reference to FIGS. 7C and 7D, can be used with any of the mixing recesses.

FIG. 7A illustrates a gas distributor 360 having a mixing recess 380 in accordance with another embodiment of the invention. The mixing recess 380 has a generally cylindrical shape with a first wall 382 defining the side of the cylinder and a second wall 384 defining the bottom of the mixing recess 380. In another embodiment, the mixing recess 380 could have a different shape, such as a rectangular shape with the first wall 382 being one of the four rectangular sidewalls. In the illustrated embodiment, the gas distributor 360 also includes two first injectors 270 positioned in the first wall 382 at diametrically opposed locations, two second injectors 272 (only one shown) positioned in the first wall 382 offset from the first injector 270 by 90°, and the third injector 274 positioned in the second wall 384. The first injectors 270 project the first gas flow into the mixing recess 380 along first vectors V₁ generally parallel to the workpiece W (not shown), and the second injectors 272 project the second gas flow into the mixing recess 380 along second vectors V₂ generally parallel to the workpiece W and normal to the first vectors V₁. The third injector 274 is oriented to project the third gas flow along the third vector V₃ into the mixing recess 380 in a direction generally normal to the workpiece W.

FIG. 7B is a schematic representation of a portion of a gas distributor 460 having a mixing recess 480 in accordance with another embodiment of the invention. The mixing recess 480 has a generally cubical shape with first walls 482 a, 482 b, and 482 c defining three sides of the cube and a second wall 484 defining the bottom of the mixing recess 480. In another embodiment, the mixing recess 480 can have a different shape, such as a pyramidical shape with the first walls 482 being three sidewalls of the pyramid. In the illustrated embodiment, the gas distributor 460 includes first injectors 270 positioned in the first walls 482 a and 482 c, second injectors 272 positioned in the first wall 482 b and a first wall (not shown) opposite the wall 482 b. The gas distributor 460 also includes a third injector 274 positioned in the second wall 484. The first injectors 270 project the first gas flow along first vectors V₁ into the mixing recess 480 at the angle σ with respect to the workpiece W (not shown). The second injectors 272 project the second gas flow along second vectors V₂ into the mixing recess 480 at an angle with respect to the workpiece W. The third injector 274 is oriented to project the third gas flow along the third vector V₃ into the mixing recess 480 in a direction generally normal to the workpiece W.

FIG. 7C is a schematic representation of a portion of a gas distributor 560 having a mixing recess 580 in accordance with another embodiment of the invention. The mixing recess 580 has a generally hexagonal shape with first walls 582 a, 582 b, and 582 c defining sides of the hexagon and a second wall 584 defining the bottom of the mixing recess 580. The gas distributor 560 includes the first injector 270 positioned in the second wall 584 and the second injector 272 positioned in the second wall 584. The first injector is oriented to project the first gas flow along the vector V₁ into the mixing recess 580 at the angle σ with respect to the workpiece W (not shown). The second injector 272 is oriented to project the second gas flow along the second vector V₂ into the mixing recess 580 at the angle α with respect to the workpiece W.

FIG. 7D is a schematic representation of a portion of a gas distributor 660 having a mixing recess 680 in accordance with another embodiment of the invention. The mixing recess 680 has a generally conical shape with a first wall 682 defining the side of the cone. In another embodiment, the mixing recess 680 could have a different shape, such as a pyramidical shape, with the first wall 682 being one of the sidewalls. In the illustrated embodiment, the gas distributor 660 includes the first injector 270 positioned in the first wall 682 and the second injector 272 positioned in the first wall 682 opposite the first injector 270. The first injector 270 is oriented to project the first gas flow along the first vector V₁ into the mixing recess 680 at the angle σ with respect to the workpiece W (not shown). The second injector 272 is oriented to project the second gas flow along the second vector V₂ into the mixing recess 680 at the angle α with respect to the workpiece W. In other embodiments, the first and second injectors 270 and 272 can be offset individually or in pairs as explained above with reference to FIG. 7A.

FIG. 8 is a schematic representation of a gas distributor 760 in accordance with another embodiment of the invention. The gas distributor 760 has a first wall 764, a second wall 766, and a third wall 768 that at least partially define a mixing recess 780. The mixing recess 780 is positioned over the workpiece W. The gas distributor 760 includes the first injectors 270, the second injectors 272, and the third injectors 274. The first injectors 270 and the second injectors 272 are interspersed along the walls 764, 766, and 768 and are positioned to project gases into the mixing recess 780. In the illustrated embodiment, many of the injectors 270, 272, and 274 can be oriented at different angles with respect to the workpiece W to facilitate mixing of the gases before deposition onto the workpiece W. In other embodiments, the injectors 270, 272, and 274 can be arranged differently, such as at different angles or positions in the walls 764, 766, and 768. In other embodiments, the gas distributor 760 can have different shapes or configurations, such as those illustrated in FIGS. 5-7D.

FIG. 9 is a schematic representation of a gas distributor 860 in accordance with another embodiment of the invention. The gas distributor 860 has a first surface 862 from which the first injectors 270 and the second injectors 272 project the individual gas flows. The injectors 270 and 272 can be arranged in pairs (including one first injector 270 and one second injector 272) across the first surface 862 of the gas distributor 860. Each first injector 270 projects the first gas along the first vector V₁ at the angle σ with respect to the workpiece W. Similarly, each second projector 272 projects the second gas along the second vector V₂ at the angle α with respect to the workpiece W. The first and second gases mix in a mixing zone 890 above the workpiece W. In other embodiments, pairs of first injectors 270 can inject a single gas flow along the first and second vectors V₁ and V₂, and pairs of second injectors 272 can inject another individual gas flow along the first and second vectors V₁ and V₂ in a different mixing zone.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims. 

1-54. (canceled)
 55. A method for depositing material onto a micro-device workpiece in a reaction chamber, comprising: passing a first gas flow through a first injector of a gas distributor along a first vector; and passing a second gas flow through a second injector of the gas distributor along a second vector that intersects with the first vector in a mixing zone exposed to and over the micro-device workpiece.
 56. The method of claim 55, further comprising mixing the first gas flow and the second gas flow in the mixing zone.
 57. The method of claim 55 wherein passing a first gas flow and passing a second gas flow occur at least partially simultaneously.
 58. The method of claim 55 wherein passing a second gas flow occurs after terminating passing the first gas flow.
 59. The method of claim 55, further comprising passing a third gas flow through a third injector of the gas distributor.
 60. The method of claim 55 wherein the first and second gas flows comprise the same gas.
 61. The method of claim 55 wherein the first gas flow comprises a first precursor and the second gas flow comprises a second precursor, and wherein passing the first gas flow and passing the second gas flow occur at least substantially simultaneously.
 62. The method of claim 55, further comprising: passing a third gas flow through a third injector of the gas distributor; and wherein passing the first gas flow comprises passing a first precursor through the first injector and then terminating the first gas flow, wherein passing the third gas flow comprises passing a purge gas through the third injector after terminating the first gas flow and then terminating the third gas flow, and wherein passing the second gas flow comprises passing a second precursor through the second injector after terminating the third gas flow.
 63. The method of claim 55, further comprising: passing a third gas flow through a third injector of the gas distributor; and wherein passing the first gas flow comprises passing a first precursor, wherein passing the second gas flow comprises passing a second precursor at least substantially simultaneously with passing the first gas flow, and wherein passing the third gas flow comprises passing a purge gas after terminating the first and second gas flows.
 64. The method of claim 55 wherein passing the first gas flow and passing the second gas flow comprise creating a vortex in the mixing zone of the first and second gas flows.
 65. A method for depositing material onto a micro-device workpiece in a reaction chamber, comprising: flowing a first gas flow through a first injector of a gas distributor into an external mixing recess in the gas distributor; and flowing a second gas flow through a second injector of the gas distributor into the external mixing recess over the micro-device workpiece.
 66. The method of claim 65, further comprising mixing the first gas flow and the second gas flow in the mixing zone.
 67. The method of claim 65 wherein flowing the first gas flow and flowing the second gas flow occur at least partially simultaneously.
 68. The method of claim 65 wherein flowing the second gas flow occurs after terminating flowing the first gas flow.
 69. The method of claim 65, further comprising flowing a third gas flow through a third injector of the gas distributor.
 70. The method of claim 65 wherein flowing the first gas flow comprises flowing the first gas flow along a first vector, and flowing the second gas flow comprises flowing the second gas flow along a second vector transverse to the first vector.
 71. The method of claim 65 wherein flowing the first gas flow comprises flowing the first gas flow along a first vector, and flowing the second gas flow comprises flowing the second gas flow along a second vector generally parallel to the first vector.
 72. The method of claim 65, further comprising creating a vortex in the mixing recess with the first and second gas flows.
 73. A method for depositing material onto a micro-device workpiece in a reaction chamber having a gas distributor, comprising: dispensing a pulse of a first gas from a first outlet in the gas distributor into an external recess in the gas distributor; and dispensing a pulse of a second gas from a second outlet in the gas distributor into the external recess in the gas distributor after terminating the pulse of the first gas.
 74. The method of claim 73, further comprising mixing the first gas and the second gas on a surface of the workpiece.
 75. The method of claim 73, further comprising dispensing a pulse of a purge gas through a third outlet into the recess of the gas distributor between the pulse of the first gas and the pulse of the second gas.
 76. The method of claim 73 wherein dispensing the pulse of the first gas comprises dispensing the first gas along a first vector, and dispensing the pulse of the second gas comprises dispensing the second gas along a second vector transverse to the first vector.
 77. The method of claim 73 wherein the dispensing procedures are repeated in serial order creating a vortex within the external recess in the gas distributor. 